Currently, arch_trigger_all_cpu_backtrace() is defined in only x86 and sparc which has nmi interrupt.
But in case of softlockup not a hardlockup, it could be possible to dump backtrace of all cpus. and this could be helpful for debugging.
for example, if system has 2 cpus.
CPU 0 CPU 1
acquire read_lock()
try to do write_lock()
,,,
missing read_unlock()
In this case, softlockup will occur becasuse CPU 0 does not call read_unlock().
And dump_stack() print only backtrace for "CPU 0". If CPU1's backtrace is printed it's very helpful.
This patch adds arch_trigger_all_cpu_backtrace() for mips architecture.
Maybe someone make better patch than this. I just suggest the idea.
---
arch/mips/include/asm/irq.h | 3 +++
arch/mips/kernel/process.c | 18 ++++++++++++++++++
2 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h
index 39f07ae..5a4e1bb 100644
--- a/arch/mips/include/asm/irq.h
+++ b/arch/mips/include/asm/irq.h
@@ -48,4 +48,7 @@ extern int cp0_compare_irq;
extern int cp0_compare_irq_shift;
extern int cp0_perfcount_irq;
+void arch_trigger_all_cpu_backtrace(bool);
+#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
+
#endif /* _ASM_IRQ_H */
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 636b074..9f51d3d 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -42,6 +42,7 @@
#include <asm/isadep.h>
#include <asm/inst.h>
#include <asm/stacktrace.h>
+#include <asm/irq_regs.h>
#ifdef CONFIG_HOTPLUG_CPU
void arch_cpu_idle_dead(void)
@@ -532,3 +533,20 @@ unsigned long arch_align_stack(unsigned long sp)
return sp & ALMASK;
}
+
+static void arch_dump_stack(void *info)
+{
+ struct pt_regs *regs;
+
+ regs = get_irq_regs();
+
+ if(regs)
+ show_regs(regs);
+
+ dump_stack();
+}
+
+void arch_trigger_all_cpu_backtrace(bool include_self)
+{
+ smp_call_function(arch_dump_stack, NULL, 1);
+}
--
1.7.0.1
